Cooling system for fuel injection nozzles



.Filed Jan. 30', 1 941 INVENTOR4 I 4 W BY ATTORNEY Patented Aug. 7, 1945ZZLES Albert '1. Bremser, Sidney, N. Y., assignor to Bendix AviationCorporation, South Bend. Inii a corporation of Delaware ApplicationJanuary 30, 1941, Serial No. 378,625 4 (cl. 123-32) This inventionrelates to internal combustion engines, and more particularly to meansfor controlling the temperature of fuel injection nozzles in solid fuelinjection angina. I

It has been heretofore proposed to cool fuel iniection nozzles bycirculating a liquid through or around the same, but this method ofcooling Y has not proved entirely satisfactory in modern engines whereinlow weight and small size per unit of power is of prime importance.'Means heretofore provided for this purpose have either entailed large,complicated units requiring the provision of. large openings in thecylinder head,

thereby reducing the strength of the cylinder and the available spacefor intake and exhaust passageacr the provision of suchsmall coolingpas:

oases that insuilicient cooling was eflected and scaling or corrosiontended to clog thecirculating It is accordinglyan oblect or the presentinventime to provide a novel cooling system for iuel injection nozzleswherein the ioregoing disadvantones are overcome.

- Another object of the invention is 9 provide novel means for coolingfuel injection nozzles by the passage of air therethrough.

A further object is to provide novel means for supplying a gaseouscooling medium to a fuel iniection nozzle. 1

The above and further objects and novel features of the invention willmore fully appear from the following detailed description when the sameis read in connection with the accompanyin drawing. It is to beexpressly understood, however, that the drawing. i for the purpose ofillustration only and is not intended to define the limits of theinvention, reference for this latter purpose being bad primarily to theappended claims.

In the drawing, wherein like reference characters refer to like partsthroughout the several views,

Fig. 1 is a detail sectional view, with parts broken away, illustratinga portion or one cylin- -der of an internal combustion engine having oneform of the invention incorporated therein;

Fig. 2 is a sectional view of the injection-nozzle or Fig. 1. thesection being taken substantially on line 2-2 of Fig. 1: and,

Fig. 3 is a detail view, partly in sectionv and with parts broken away,illustrating anotherembodiment of the invention; V p1As illustrated inI'igs. 1 and 2, by way of exam- 6 may be reciprocated in the usualmanner.-

Mounted on the cylinder is a cylinder head which is providedvwith anintake passage 8 controlled b a poppet valve 8 and an exhaust passage(not shown) that may be diametrically disposed with respect to passage8.

Centrally disposed in cylinder head I is a fuel inJection nomle N whichis so constructed that a cooling medium may be advantageously circulatedtherethrough. The particular nozzle illustrated, by way of example, isdisclosed and claimed in my prior copending application. Serial No.360,729, filed October 11, 1940, and comprises a nozzle holder body Ithaving a. relatively small external diameter and a central bore H whichis enlarged ternal peripheral shoulder it that is adapted to engage aninternal shoulder in the receiving openins provided in cylinder head 1.ior nomle N.

interposed between the lower end or body it and an internal shoulder itin tip holder i4 and extending downwardly through a reduced portion ofsaid holder is a spray tip ii and a valve guide wit. The latter has asliding fit in nut i4 and is provided with a central borein which avalve 88 is slidably received. A reduced portion adjacent one embodimentof the invention is combined with an we mm 5 m which a piston positionby suitable resilient means, such as coil the lower end of valve I9 issurrounded by an enlarged bore in member 18, thereby forming afuelpressure chamber 20, and the cone-shaped lower end of the valve isadapted to engage a valve seat in the guide member to thereby controlthe flow of fuel through a passage 2| into a central passage 22 of spraytip I! and thence into the combustion chamber of cylinder 5.

1 For'the'purpose of limiting the opening movement of valve 89 tothereby prevent the injection of excessive charges oi fuel and, hence,increase the eiliciency and operating characteristics of the engine inwhich the nozzle is employed, particularly over long periods of use, arelatively thin metallic plate 23 is interposed between member i8 andbody l0. Said plate has. a central opening through which a reducedportion of valve i9 freely extends but which has a diameter somewhatless than the main body portion of said valve. Plate 23 is preferablymade or hard, closeegrained steel, or of suitable hardened metal whichwill resist v wearer internal structural collapse during the continuoushammering of valve i8 against the v same;

Valve is is normallyheld in seated or closed spindle as, that freelyextends through central bore II in body It. The lower end of spindle orrod 25 is preferably recessed for freely receiv- ,ing the reduced upperend of valve ll so that there will be little or-no tendency towardbiasing the valve in its guide I. Said spindle is provided adjacent itsupper end with a collar 33 on which one end of spring 34 is seated andthe other end of the spring engages the. inner end of a plug nut oradjusting screw 31' which is externally threaded to engage screw threadsl3. Liquid "fuel may be supplied to the engine cylinder through theabove-described nozzle from a supply conduit 23 (Fig. 2) whichcommunicates with a fuel passage 2! provided in body ll. Said passagecommunicates with pressure chamber 30 assnsos vital portion of theinjection nozzie at a comparatively low temperature.

Novel means are provided for supplying air as a cooling medium tochamber 33 and the other cooling passages of nozzle N. ,In the formshown, said means comprises a scoo 03 positioned in. the intake passage3 of the engine and connected by means of a suitable conduit 44 topassage 3! in the nozzle. Thus, when air is drawn into cylinder 5 duringthe normal operation of the engine, a portion of the air rushing throughpassage I is picked up by scoop 43 and directed through the coolingpassages of the noszle and-exhausted to atmosphere through a conduit Iconnected with the outer. end of passage 33. The. air thus circulatedthrough the nozzle is ordinarily cleaned by passage through asuitthrough an opening in plate 23 and a passage 33 in guide member 13.Thus, when pressure is applied to the fuel in supply line 38 and, hence,in chamber 3|, valve II will be lifted from its seat against theyielding pressure of spring 34 and a charge of fuel will be injectedinto the engine cylinder through passages 3| and 33. The openingmovement of valve [8 is limited, as

pointed out above, by plate 23 so that the valve will be quickly seatedagain by spring 24 as soon as-the fluid pressure in chamber/ is reduced.

In the form shown. the circulatory system for a cooling medium withinnomle N comprises a cup-like shell or casing member 3i, which slidablyextends through the reduced portion of sleeve nut I4 and has an externalflange '32 that extends between shoulder l6 of said nut and an externalshoulder on the enlarged upper end of spray'tip IL The lower reduced endof member 3| isinternallv threaded for cooperation with the externallythreaded lower end of spray tip I]. The enga ing shoulders of members-l1and 3| form a fluid and gas-tight seal. Within member 3| an inte ediateportion of nozzle tip I1 is preferably undercut to thereby form theinner wall of an annular cooling chamber 33. 7

Shell or casing 3| is preferably-constructed of stainless steel or othersuitable metal so that the wall thereof maybe relatively thin andflexible and yet be able to withstand the high heat and pressure towhich it must be subjected. In

assembling the nozzle, a tight Joint is first eff ected at-the eng inshoulders adjacent the lower ends of members I! and II by threadingmember 3|- onto member H. -Member 3| is so constructed that when it isthus applied to memher I] there is a veryslight clearance between v Vflange 32 and the enlarged or flanged upper end of member ILtherebyinsuring a tight seal when flange 32 is clamped between shoulder I! ofnut l4 andtip member II. By reason of the stantially surround the seatfor needle valve 13 .so-that the coolinimedium will maintain thisflexibility of the flange 32, the slight clearance between it and memberII, as mentioned above, is

taken up when} not I4 is screwed tightly into place. 7

A suitable cooling medium may be conducted to and from chamber 33through passages 35 andv 38 in body It; suitably positioned openings inplate 23, 31 and 33 in guide member It, and openings 38 and 43 in'theflanged upper portion of tip piece I'L Preferably the lower ends ofpassages 31- and 38 communicate with arcuate grooves ll and 43 in thelower face of able cleaner before it enters the intake manifold of theengine. Large quantities of air may thus of air through nozzle N by theapplication of suction to one of the passages 35 or 36. As shown in'Fig.3, passage 35 is connected through a pipe 44' and a conduit 46 incylinder head 'I' to the intake passage I of the engine in such a mannerthat the suction created during the intake stroke of theengine pistoniseflective to draw cooling air through the nozzle from inlet conduit I45'. If desired, the cooling air may be supplied zle either toatmosphere or,- as illustrated in to conduit by a suitable compressor orpump 41 and exhausted through passage 35 of the noz- Fig. 3, to intakepassage 3' through conduits-41',

for the purpose of superchargins the e ine cylinder.

There is thus provided novel-apparatus embodying novel means andemploying a novel method for cooling injection nozzles of solid fuelinjection engines. Said apparatus is so constructed as to occupy aminimum of space in the cylinder head or the like. Additionally, air isemployed as the cooling medium whereby the cooling passages may be maderelativelysmali to obtain adequate cooling without the necessity forfrequent cleaning andoverhauling of the nomle. The life as well as theefllciency of the nozzle is materially increased.

Although only a limited number of the embodiments of the invention areillustrated and described in detail, it is to be expressly understoodthat the invention is not limited thereto. For

example,- the invention is applicable to twostroke ycie engines as wellas to four-stroke cycle ngines and air may be supplied simultaneously toall of the nozzles of a multi-cylinder engine from a common manifoldconnected to one or-more of the engine intake passages or 7 othersources of suctionor compression to thereby insure a continuous flow ofair through each of the injection nozzles; Various changes may also bemadein the design and arrangement of parts illustrated without departingfrom the spirit and guide member it. Each of said grooves extends lessthan but taken together they sub-- scope of the invention as the samewill now be understood by those skilled in the art. For a definition ofthe limits of ,the invention. reference is had primarily to the appendedclaims.

What is-claimed is:

1. The combination with an internal combustion engine having an intakepassage of a fuel injection nozzle having cooling passages therein, anair scoop in said intake passage of the engine, and means connectingsaid scoop with said nozzle whereby air is directed from said intakepassage through said cooling passages during operation of the engine. a

2. The combination with an internal combustion engine having an intakepassage of a fuel injection nozzle having cooling passages therein,

and means including air deflecting means extending into the air streamflowing through said passages for cooling said nozzle.

' intake passage for directing air to said cooling 5 pressure.

3. The combination with an internal combustion engine having an intakepassageot a; fuel injection nozzle having cooling passages therein,means for diverting air from said intake passage through the coolingpassages in said nozzle, and means for directing air from said coolingpassages to said intake passage.

4. The combination in an internal combustion engine having an intakepassage of a fuel injec tion nozzle having passages for a cooling mediumtherein, means for diverting air from said intake passage through thepassages insaid nozzle, and means for .directing air from saidlast-named passages to said intake passage at a point of low ALBERT 'r.BREMSER.

